What is the best tip for your overhead which actually worked for you?

My overhead used to be the worst part of my game. Until I started watching how Laver jump off his back foot, swing up like a hammer hitting a nail upwards, and then the back foot balancing out to the right. Then I was back in business.

The other one that worked for me is to aim the tip at the ball, then set the racquet face behind my head, like an Ivanisevic serve and come forward off the front leg. I saw a wiry Vietnamese guy do this quite well, and he was joking the whole time.

Share with us your insight on the overhead, that, often times, least practiced shot.